/**
 * \file mutex.h
 * \brief Multiprocessor safe mutex
 * \author Corey Tabaka
 */

/*
   Copyright 2005 Corey Tabaka

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

#include <ktypes.h>
#include <spinlock.h>
#include <Queue.h>

#ifndef __KERNEL_MUTEX_H__
#define __KERNEL_MUTEX_H__

/*
 * Standard Mutexes
 */

typedef struct {
	int_mutex_t lock;
	volatile int count;
	
	// queue of threads waiting on this mutex
	Queue threads;
} mutex_t;

#define MUTEX_UNLOCKED { INT_MUTEX_UNLOCKED, 0 }

#ifdef __cplusplus
extern "C" {
#endif

void mutex_init(mutex_t *mutex);
void mutex_wait(mutex_t *mutex);
int mutex_try(mutex_t *mutex);
void mutex_signal(mutex_t *mutex);

#ifdef __cplusplus
}
#endif


/*
 * Semaphore
 */

typedef mutex_t semaphore_t;

#define SEMAPHORE_INIT(count) { INT_MUTEX_UNLOCKED, (count) }

#ifdef __cplusplus
extern "C" {
#endif
 
void semaphore_init(semaphore_t *, int);
void semaphore_wait(semaphore_t *);
void semaphore_signal(semaphore_t *);

#ifdef __cplusplus
}
#endif

#endif
